1. Field of the Instant Disclosure
The instant disclosure relates to a method of anodic treatment for a metal workpiece combined with a non-metallic material; in particular, to a method of metal surface treatment technology to form a colorful appearance on the metal workpiece.
2. Description of Related Art
Following the progress of metalworking technology, more and more portable electronic products such as mobile phones or notebooks are equipped with a metal shell. However, the metal shell will affect the transmission and reception of wireless signals, which results in bad reception of signal.
To improve the problem of bad reception, a technology has been developed to integrally combine a metal part and a plastic part. Thus, the wireless signal can be transmitted through the plastic part for improving a better wireless signal communication.
Concerning the above mentioned art, after the metal shell, which combines a metal part with a plastic part, is processed with anodic treatment, a gap between the metal part and the plastic part easily happens to create uneven spots of different colors. Thus, the defect-free rate of the product's appearance is lower. To clean the above mentioned spots, one way is to process with pickling by nitric acid, surface conditioning agent, and water washing, so as to remove the residual acid agent in the gaps between the metal part and the plastic part. However, if the number of cleanings or the time is not controlled well during cleaning the metal shell, it easily results in environmental failure testing of the metal shell, such as, thermal cycling testing, salt spray testing, sweat testing . . . etc.
To address the above issues, the inventors strive via industrial experience and academic research to present the instant disclosure, which can effectively improve the limitations described above.